The overall objective is an understanding of visual receptors and of neural processes, whether in the eye or brain. Psychophysical experiments are proposed, which, with mathematical analysis, may reveal the dynamics of the above processes. For receptors, the question to be investigated is the nature of the delay between light absorption and receptor response. Two competing hypotheses will be tested: that the delay is due to a diffusion process, versus a delay due to about 10 successive transmission and amplification stages. Lateral inhibition between adjacent parts of receptive fields will be studied, in particular the role of color-opponent mechanisms. Visual stimuli will consist of patterns presented on a color TV monitor. A recent hypothesis, to the effect that the visual system operates on spatial frequencies in a manner analogous to that of the ear on temporal frequencies, will be investigated, also using the TV monitor.